Means for and method of producing contraction joints



Feb. 13, 1968, J, O ET AL 3,368,464

MEANS FOR AND METHOD OF PRODUCING CONTRACTION JOINTS Filed Sept. 24, 1965 INVENTORS JAMES T. THORP JR..

ATTORNEYS United States Patent Ofiicc 3,368,464 Patented Feb. 13, 1968 3,368,464 MEANS FOR AND METHOD OF PRODUCING CONTRACTION JOINTS James T. Thorp, Jr., and Donald K. Brazee, St. Louis, Mo., assignors to Lambert Products, Inc., St. Louis, Mo., a corporation of Missouri Filed Sept. 24, 1965, Ser. No. 489,995 9 Claims. (Cl. 9418) ABSTRACT OF THE DISCLOSURE The contraction joint is sealed by a device comprising an upper strip of open-tubular material which is laterally compressible, and provides a pavement seal. The upper strip is attached to a lower strip which includes a pair of laterally, flexible legs, depending from the upper strip, the flexible legs being provided with elongate anchorage elements extending laterally from the legs. The legs have an inverted V-shape and are continuous at the apex to provide a second seal.

A method of forming a double-sealed waterproof joint is also disclosed which entails clamping the sealing device temporarily during insertion of the sealing device into the wet concrete.

This invention relates generally to improvements in the means for and the method of producing sealed contraction joints suitable for roads, floors and similar structures. It has to do particularly with an improved contraction joint for use between sections of concrete highway pavement which are subject to longitudinal and lateral movement because of thermal expansion and contraction of the concrete as temperature changes occur and also contraction of the concrete because of inherent shrinkage characteristics of the concrete.

A concrete pavement which is not provided with contraction joints, or is provided with inadequate joints, will be subject to stresses set up within the pavement slab which will inevitably result in the appearance of random cracking throughout the slab.

Many attempts have been made to provide suitable contraction joints, the early ones consisting simply of filling the gap left between the abutting edges of the highway pavement slabs with a plastic material such as tar. This joint was unsatisfactory because the tar was forced out of the gap as the gap closed upon expansion of the slab and did not return when the slab contracted. Later methods have been more successful, but almost all of them suffer from the disability of requiring a pre-formed groove be made in a continuous slab or an expensive sawcut to be made in the slab preparatory to filling with a plastic material as used in the earlier type. Alternatively, an individual elastic strip type sealant was used which was normally installed by forcing it into the pre-formed groove or sawcut. Because these strip type expansion sealants are positioned after the concrete has set, they invariably have no anchorage provision to hold them in place and rely largely on the friction between the compressed sealant and the edges of the slab to hold them in the pre-formed groove. Consequently, as traffic passes over the area of the joint, a downward pressure is exerted on the subgrade. If moisture and/or mud are present below the slab, they tend to be forced up into the joint gap and exert a pressure on the underside of the sealant. Without the provision of a shielding and anchoring device such pressure might force the strip out of place, and thus damage or destroy the joint.

The principal object of the present invention is to provide a sealing device which will eliminate the previously mentioned disabilities so commonly associated with contraction joints, and to provide a method of installing the device which may be accomplished easily and effectively.

An important object is achieved by the provision of a sealing device that can be placed in a newly poured pavement while the pavement is still wet.

Another important object is to provide a sealing device which is under permanent lateral compression with the pavement thus ensuring that moisture, dirt, or other matter will not enter the joint gap from the roadway surface.

A further important object is realized by a sealing strip located below the surface of the pavement slab to avoid the objectionable surface projections which are so often present at highway pavement contraction joints.

Still another object is that which is achieved by providing an anchorage attached to and depending from the elastic seal which prevents the sealing device from floating to the surface of the wet pavement, the anchorage being embedded in the pavement.

Another important object is afforded by the provision of the continuous strip anchorage, attached to and below the continuous seal, which enables the depth of the joint to be controlled by varying the manufactured length of depending twin legs to suit the requirements of the particular slab. An advantage realized is that the structural thickness of concrete remaining under the anchorage is predictable and ensures controlled cracking of the pavement along predetermined lines at the joint.

Yet another important object is achieved in that the anchorage provides a physical barrier, in addition to that provided by the seal, against the passage of water downwardly through the joint, and equally important, the anchorage provides a barrier against upward water or other pressure which might otherwise force the seal out of position in the joint.

Another important object is provided by the method 0 forming a contraction joint using the sealing device which includes the steps of exhausting air from a multicellular sealing strip, inserting the sealing device into newly placed, wet pavement while retaining the vacuum in the sealing strip, and then removing the vacuum after the pavement has set.

Still another important objective is attained by utilizing a vibrating clamping tool to install the sealing device in the pavement, the tool being released from the sealing device and withdrawn from the wet pavement while vibrating.

It is an important objective to provide a sealing device for a contraction joint which is simple and durable in construction, economical to manufacture and install, and highly eflicient in operation.

The foregoing and numerous other objects and advantages of the invention will more clearly appear from the following detailed description of a preferred embodiment, particularly when considered in connection with the accompanying drawing in which:

FIG. 1 is a fragmentary isometric view of the sealing device;'

FIG. 2 is a cross-sectional view illustrating the upper strip portion of the sealing device in its evacuated, laterally compressed state;

FIG. 3 is a fragmentary cross-sectional view illustrating the sealing device installed with a clamping tool;

FIG. 4 is a fragmentary cross-sectional view showing the sealing device installed but still under vacuum;

FIG. 5 is a fragmentary cross-sectional view showing the sealing device installed but with the vacuum released from the upper strip portion, and the pavement contracted, and

FIG. 6 is a view similar to FIG. 5, but showing the relative positions of the component parts when the pavement contracts further.

Referring now by characters of reference to the drawing, and first to FIG. 1, it is seen that the elongate sealing device generally indicated by consists of an elongate upper strip portion referred to by 11 formed of neoprene or like material, and a depending lower strip portion referred to by 12 formed of a plastic such as polyethylene.

The upper strip portion 11 is multicellular and is constructed essentially of three elongate, integral tubes 13, 14 and 15 disposed in side by side relation. The roof 16 of each tube 13-15 inclusive is upwardly convex.

One of the side tubes 13 has a substantially flat and vertical, outermost side wall 17. Partially forming the bottom wall of the side tube 13 is a substantially horizontal shoulder 20 extending inwardly from the outermost side wall 17. The remaining portion of the bottom wall of tube 13 consists of a diagonal wall portion 21 ex tending upwardly and inwardly from the shoulder 20 to a common, substantially vertical side wall 22 integrally interconnecting the side tube 13 with the intervening tube 14.

The other side tube 15 is identical, yet reversely constructed. For example, the side tube 15 includes an outermost, substantially flat and vertical side wall 23. Extending inwardly from the side wall 23 is a substantially horizontal shoulder 24 that partially constitutes the bottom wall of tube 15. The remaining portion of the bottom wall of side tube 15 consists of a diagonal wall portion 25 extending upwardly and inwardly from the shoulder 24 to a common, substantially vertical side wall 26 integrally interconnecting the side tube 15 with the intervening tube 14.

The bottom of intervening tube 14 includes a pair of downwardly converging walls 27 and 30 extending from the inside walls 22 and 26 respectively, and merging at their lower ends to provide a depending neck 31. Formed in the lower margin of neck 31 is an elongate groove 32.

The upper strip portion 11 is of a resilient material that can be laterally compressed, as by evacuating the air from the tubes 13-15 inclusive, from the expanded shape shown in FIG. 1 to the substantially fiat, retracted shape shown in FIG. 2. In the compressed, retracted state shown in FIG. 2, the outermost side walls 17 and 23 are maintained substantially vertical and flat, and the shoulders 20 and 24 are maintained substantially horizontal and flat, yet moved to a position in which the shoulders 20 and 24 meet with substantially vertical side faces of the neck 31.

The lower strip portion 12 is bifurcated to form an inverted, substantially V-shape having a pair of elongate legs 33 and 34 integrally connected together at one end 35 to form an apex. This apex end 35 includes an upstanding tongue 36 that interfits the neck groove 32 and is bonded to the upper strip portion 11 with a suitable adhesive.

The length of legs 33 and 34 depending from the neck 31 are relatively thin and laterally flexible. The lower extremities 37 and 40 of legs 33 and 34 respectively are relatively thicker and inflexible. It will be understood that these leg extremities 37 and 40 abut when the legs 33 and 34 are closed together in order for their outer faces to be substantially vertical and parallel, merging continuously with the side faces of the depending neck 31.

Projecting laterally outward from each of the leg extremities 37 and 40 is an elongate rib 41 and 42 respectively, the ribs 41 and 42 extending laterally beyond the side faces of the legs 33 and 34. The cooperating leg extremities 37 and 40, together with their integral ribs 41 and 42 respectively, constitute anchorage means.

As shown in FIG. 3, an elongate clamp 43 is adapted to insert the sealing device 10 into newly placed pavement 44 such as concrete. The clamp 43 includes a pair of clamp arms 45 connected at one end by hinge 46. Preferably, the clamp arms 45 are provided with a plastic coating, such as Teflon to prevent the sealing strip material from adhering and to facilitate removal of the clamp 43 from the pavement.

Before installation of the sealing device 10 air is exhausted from the multicellular upper sealing strip portion 11 by passing it between a set of side rollers or by other means such as utilizing the clamp 43. These side rollers or clamp arms 45 would engage the side walls 17 and 23 and would laterally compress the upper strip portion 11 from the fully expanded state shown in FIG. 1 to the fully compressed, retracted state shown in FIG. 2. The vacuum is retained by sealing or clipping the ends of the upper strip portion 11.

To install the sealing device 10 and form a contraction joint, the device 10, with the upper sealing strip portion 11 in its exhausted, compressed condition, and with the flexible legs 33 and 34 in a closed position, is held securely along its length by pressure from the embracing clamp arms 45 of the elongate clamp 43. While so held, as is illustrated in FIG. 3, the sealing device 10 is inserted into the newly poured and wet pavement 44. This placement of the sealing device 10 is accomplished by pushin the device 10 into the pavement 44 with the lower strip portion 12 foremost until the roofs 16 of the upper sealing strip portion 11 lie slightly below the pavement surface 47. To facilitate the insertion of the device 10 with the least disturbance of the pavement 44, the device 10 is vibrated by clamp 43 as it is moved inwardly into place.

After the sealing device 10 has been positioned, the holding pressure exerted on the device 10 by the clamp arms 45 is released, and the clamp 43, while still vibrating, is withdrawn from the pavement 44. As the clamp 43 is withdrawn, the wet pavement 44 flows immediately about and into contact with the upper sealing strip portion 11 and the lower strip portion 12. It will be understood that the hydraulic pressure of the pavement 44 exerted on the outer side faces of the legs 33 and 34 is suflicient to maintain the closed position of the leg extremities 37 and 40. The anchoring ribs 41 and 42 coact with the pavement 44 to prevent the sealing device 10 from floating, or otherwise moving outwardly after it has been placed.

FIG. 4 illustrates the disposition of the wet pavement around the device 10 at this final stage of the installation. It will be noticed that the fluid nature of the pavement 44 forms seats 50 and 51 which cooperate with and engage shoulders 20 and 24 respectively. The coacting shoulders 20 and 24 and seats 50 and 51 provide stops preventing the upper sealing strip portion 11 from being pushed into the gap 52 defined by the lateral joint walls, as the gap widens upon pavement contraction as shown in FIG. 6, after the pavement 44 has set.

When the pavement 44 has set, the sealing strip vacuum is released and air pressure is introduced into the tubes 13-15 by piercing the upper strip portion 11 or by removing the end seals.

Upon contraction of the pavement 44 under falling temperatures, or because of inherent shrinkage characteristics, or a combination of both effects, the pavement 44 will crack as indicated by 53. This controlled cracking takes place at the joint formed by the sealing device 10, and specifically between legs 33 and 34, because the pavement 44 is substantially thinner and consequently much weaker at this point. Following this cracking, there will be a natural tendency for the distance between the lateral joint walls to increase. However, because of the release of the vacuum in the upper sealing strip portion 11, the strip portion 11 tends to assume its original shape and will resiliently expand as the lateral dimension between joint walls increases to keep the gap 52 filled and weatherproof. Conversely, upon thermal expansion of the pavement 44, the multicellular upper sealing strip portion 11 is laterally compressed to accommodate any variation in distance between the lateral joint walls.

It will be understood that when the gap 52 tends to increase, the flexible nature of the legs 33 and 34 of the lower strip portion 12 will allow the legs 33 and 34 to part and spread while the leg extremities 37 and 40 by reason of the embedment of anchorage ribs 41 and 42, remain in contact with the lateral joint walls. Thus, positive anchorage capability is retained, and the upper sealing strip portion 11 is prevented from working upward and out of the gap 52. As previously mentioned the lower anchorage strip portion 12 also forms a positive seal against the upward movement of matter such as water, which often collects beneath highway paving slabs, through the joint or under the upper strip portion 11.

Moreover, it will be understood that as the legs 33 and 34 spread apart upon contraction of the pavement 44 under the pulling action of the anchorage means, formed by the leg extremities 37 and 40 and their associated ribs 41 and 42 respectively, the vertical length component of the legs 33 and 34 tends to shorten, and, therefore, the legs 33 and 34 exert a downward pull on the upper strip portion 11 which causes the strip shoulders 20 and 24 to engage their cooperating pavement seats 50 and 51 respectively under pressure to provide an efiective seal and to preclude downward movement or displacement of the upper strip portion 11. The lateral flexing action of the legs 33 and 34 does not adversely affect or change the interengagement of the strip shoulders 20 and 24 and their associated pavement seats 50 and 51. This interengagement is maintained at all times.

Although the invention has been described by making detailed reference to a single preferred embodiment, such detail it to be understood in an instructive rather than in any restrictive sense, many variations being possible within the scope of the claims hereunto appended.

We claim as our invention:

1. A sealing device for forming a contraction joint, comprising:

(a) an elongate strip having a cellular upper strip portion of resilient material, the upper strip portion being laterally compressible and resiliently expansible, and

(b) a lower strip portion including a pair of elongate continuously formed, laterally flexible legs depending from the upper strip portion, the inside face of the legs providing a waterproof physical barrier between the joint,

(c) the legs having relatively inflexible extremities predetermining a bending line of the flexible legs, and

(d) anchorage means on and extending laterally from the extremities.

2. A sealing device for forming a contraction joint,

comprising:

(a) an elongate strip having a tubular upper strip portion of resilient material, the upper strip portion being laterally compressible and resiliently expansible, and

(b) an inverted, substantially V-shaped lower strip portion including a pair of elongate legs depending from the upper strip portion,

(c) the legs having laterally flexible, thin lengths continuously joined together at the apex, and having relatively thicker, inflexible extremities the juncture between the two providing a bend line determining the commencement of the bending of the flexible portion, and

(d) an elongate anchoring rib on and extending laterally outward from each leg extremity.

3. A sealing device for forming a contraction joint,

comprising:

(a) an elongate strip having a cellular upper strip portion of resilient material, the upper strip portion being laterally compressible and resiliently expansible,

(b) the upper strip portion being provided with an elongate groove, and

(c) an inverted substantially V-shaped lower strip 6 portion including a pair of elongate, laterally flexible legs joined together at the apex,

(d) the lower strip portion including an elongate tongue at the apex interfitting the groove and bonded to the upper strip portion.

4. A sealing device as defined in claim 3, in which:

(e) the lower strip portion depends from the upper strip portion,

(f) the legs have laterally flexible thin lengths, and have relatively thicker inflexible extremities, and

(g) an elongate anchoring rib is provided on and extends laterally outward from each leg extremity.

5. A sealing device for forming a contraction joint, comprising: 4

(a) an elongate strip having an upper strip portion of resilient material, the upper strip portion being laterally compressible and resiliently expansible,

(b) the upper strip portion having a plurality of elongate, laterally adjacent and interconnected tubes, the tubes having substantially vertical side walls,

(c) each of the tubes comprising the sides of the upper strip portion having a floor partially defined by a substantially horizontal shoulder extending inwardly from the outermost side wall of the tube,

(d) a tube intermediate the side tubes having downwardly converging bottom wall portions forming a depending neck, the neck being provided with an elongate groove,

(e) the shoulders remaining substantially horizontal during compression and expansion of the upper strip portion, and

(f) a bifurcated lower strip portion including an end and a pair of elongate, laterally flexible legs joined together at the end, and

(g) an elongate tongue on the said end and interfitting the groove and connected to the neck.

6. A sealing device as defined in claim 5, in which:

(h) the depending neck has substantially vertical side surfaces, and

(i) the substantially horizontal shoulders meet the substantially vertical side surfaces of the neck upon lateral compression of the upper strip portion.

7. A sealing device as defined in claim 5, in which:

(h) the legs have laterally flexible thin lengths, and have relatively thicker inflexible extremities, and

(i) the anchorage means includes an elongate rib on and extending laterally outward from each leg extrernity.

8. The method of forming a joint between adjacent slabs of pavement using an elongate sealing device having a cellular upper strip portion of resilient material to provide a first barrier, and a lower strip portion including a pair of elongate, laterally flexible legs continuously joined at the apex to provide a V-shaped configuration and depending from the upper strip portion and including anchorage means at their extremities to provide a second barrier, the method comprising the steps of:

(a) exhausting the air from the cellular upper strip portion to compress the upper strip portion laterally,

(b) inserting the strip into the wet pavement while maintaining the vacuum in the upper strip portion whereby to embed the upper strip and the legs in the concrete, and

(c) releasing the vacuum from the upper strip portion after the pavement has set to allow lateral expansion of the upper strip portion against the pavement, the upper strip providing a first water impervious barrier, the legs providing a second water impervious barrier.

9. The method of forming a joint between adjacent slabs of pavement using an elongate sealing device having an oppositely faced upper tubular strip of resilient material, and an anchorable lower strip portion, the method comprising the steps of:

(a) compressing the upper tubular strip laterally by applying clamping pressure simultaneously along the continuous length of each face to exhaust the air from the ends of the tubular strip and reduce the volume of void in the tubular strip substantially While retaining the alignment of the strip,

(b) clipping each end of the tubular strip while maintaining clamping pressure,

(c) inserting the clamped and clipped tubular strip into the wet pavement,

(d) releasing the clamping pressure, the clips preventing the return of the tubular strip to its original shape, and

(e) then removing the clips when the pavement has set.

References Cited UNITED STATES PATENTS FOREIGN PATENTS 5/1957 Italy.

JACOB L. NACKENOFF, Primary Examiner. 

